Information Security system design basics second week study summary

First, the experiment

1. In-depth understanding of computer systems (1) Linux Fundamentals

A.linux command

Command-option-parameter ( 选项 a switch that adjusts the execution behavior of a command, 选项 depending on whether the command is displayed differently.) 参数refers to the object that the command is acting on. ）

B.man command

Man find commands by helping documents Man-k can help us learn commands I think this command is really good for us, that is, the English version of the experimental building looks dizzy

Combined with the grep command and pipeline that you learned later, you can find multiple keywords: man-k 1 | grep Key2 | grep Key3 | ...

C.chat command

Although the man is very important, but some commands to see the help is not used, beginners need an example, cheat is the small copy of the side

(2) Linux C language Programming Foundation

A.vim

Vim or to follow the tutorial specific practice, with almost one hours to follow the tutorial practice or not very skilled, it seems to be son ah concrete practice in a lot of use in order to integrate through.

Specific VIM exercises I'll do it again with the next experiment.

b.gcc

You can compile the program and also a cross-platform compiler.

• Preprocessing: Gcc–e hello.c–o hello.i;gcc–e Call CPP
• Compilation: Gcc–s hello.i–o hello.s;gcc–s Call CCL
• Compilation: Gcc–c hello.s–o hello.o;gcc-c Call as
• Link: gcc hello.o–o hello; gcc-o call ld

C.gdb

Recommended to use CGDB, better than GDB, familiar with the VC debugging methods, you can use DDD. Note Use GCC to compile with the "-G" parameter.

• GdB Programm (Start gdb)
• B Set Breakpoints (4 breakpoints are set: Line breakpoint, function breakpoint, conditional breakpoint, temporary breakpoint)
• Run starts running the program
• BT Print function Call stack
• P View variable values
• C continue running from the current breakpoint to the next breakpoint
• N Single Step operation
• S Single Step operation
• Quit Quit GDB

D. Practice

Using Vim to enter code

2.Vim Editor

(1) Vim Quick Start

A. Normal mode

Normal mode commands often require an operator end. For example, the normal mode command dd deletes the current row, but the first "D" can be followed by another move command instead of the second one d , such as a "J" key that moves to the next line to delete the current row and the next row. You can also specify the number of commands to repeat, 2dd (repeat dd two times), and dj the effect is the same. In normal mode, there are many ways to get into insert mode. The more common way is to press a (append/append) or i (insert/insert) key.

B. Insert mode

In this mode, most keystrokes insert text into the text buffer. Most new users want this mode to persist throughout the text editor editing process.

In insert mode, you can press the ESC key back to normal mode.

C. Visual modes (visual mode)

This pattern is similar to normal mode. However, the move command expands the highlighted text area. The highlighted area can be a character, a line, or a piece of text. When a non-moving command is executed, the command is executed to the highlighted area. Vim's "text object" can also be used in this mode as the move command.

D. Selection mode (select modes)

In this mode, you can use the mouse or cursor keys to highlight the selection of text, but the input of any character, Vim will use this character to replace the selected highlighted text block, and automatically enter the insertion mode.

E. Command line mode

In command-line mode, you can enter text that will be interpreted and executed. For example, execute commands ( : keys), search ( / and ? keys), or filter commands ( ! keys). After the command is executed, VIM returns to the pattern before the command-line mode, usually in normal mode.

F.ex mode (Ex mode)

visualCommands can execute multiple commands at once before leaving the ex mode.

G. Mode conversion

Vim starts into normal mode, in insert mode or command line mode, just press Esc or Ctrl+[ (this is no use in the VIM course environment) to enter normal mode. In normal mode i , press (insert) or a (attach) keys to enter the insert mode, in normal mode press : enter command line mode. In the command line mode, enter the wq carriage return and save and exit Vim.

Enter Vim

A. Use the VIM command to enter the Vim interface

Vim is appended with the file name that you want to open, or that does not exist (then as a new file). Open the Xfce terminal and enter the following command $ vim practice_1.txt

Vim editor can also be opened using Vim directly, but no files will be opened. $ vim   Enter the command line mode and the :e 文件路径 same file can be opened.

B. Cursor movement

After entering Vim, press the i key to enter insert mode. Press Esc Enter normal mode, use the arrow keys in this mode or,,, the h j k l Key can move the cursor.

Key	Description
h	Left
l	Right (lowercase L)
j	Under
k	On
w	Move to the next word
b	Move to the previous word

C. Enter insert mode

Use the following key in normal mode to enter insert mode, and to start typing from the corresponding position

Command	Description
i	Edit at current cursor
I	Insert at beginning of line
A	Inserting at the end of a row
a	Insert an edit after the cursor
o	Insert a new row after the current row
O	Insert a new row before the current line
cw	Replace the character from the position of the cursor to the end of a word

Note that each time you go back to normal mode to switch to insert mode in a different way

D. Saving a document in command-line mode

Enter the : command line mode from normal mode, enter w a carriage return, and save the document. Enter to save the :w 文件名 document as a different file name or save it to another path

E.

exit vim in command line mode

Enter : command line mode from normal mode, enter wq return, save and exit edit

Command	Description
:q!	Force quit, do not save
:q	Exit
:wq!	Force Save and exit
:w <文件路径>	Save As
:saveas 文件路径	Save As
:x	Save and exit
:wq	Save and exit

Out of vim in normal mode

Normal mode input Shift+zz can be saved out of vim

Delete vim text information in normal mode

Go to normal mode and use the following commands to quickly delete text:

Command	Description
x	Delete the character that the cursor contains
X	Delete the previous character of a cursor
Delete	Withx
dd	Delete entire row
dw	Delete a word (not in Chinese)
d$OrD	Delete to end of line
d^	Delete to beginning of line
dG	Delete to end of document
d1G	Delete to document header

In addition, you can add a number to the command before it, indicating that multiple rows are deleted at once, such as:

2ddRepresents deleting 2 rows at a time

(2) Vim document editing

Vim Repeat command

A. Repeat Last Command

In normal mode . (decimal point) means the last command operation is repeated

Copy the test file to a local directory:$ cp/etc/protocols.

Open file for editing:$ vim Protocols

Normal mode input x , delete the first character, the input . (decimal point) will be deleted again a character, in addition to also can be repeated dd delete operation

B. Executing commands of the same number of times

Enter Normal mode input N<command> , n indicates the number of repetitions followed

Open file file for editing

$ vim protocols

• Input 10x , delete 10 consecutive characters
• Input 3dd , 3 lines of text will be deleted
• In normal mode, you can also dw daw delete a word with or (delete a word)

Quick Jump for Cursors

In normal mode, the following command allows the cursor to be quickly reversed to the specified position, we discuss the rapid implementation of the inline jump and in-line jump

A. Inter-row jumps

Command	Description
nG(n shift+g)	Cursor moves to nth row (if no line number is displayed by default, enter command mode first :set nu to display line numbers)
gg	Cursor moves to the first row
G(SHIFT+G)	To the last line

Tip: After you have completed the jump, you can use the Ctrl+o quick go back to the previous (before the jump) cursor position

B. In-line jump

In normal mode, use the following command to jump within a line in a word

Command	Description
w	To the beginning of the next word
e	To the end of the next word
b	To the beginning of the first word
ge	To the end of the previous word
0Or^	to the wardrobe.
$	To end of line
f<字母>	Search backwards < letters > and jump to the first matching position (very useful)
F<字母>	Search forward < letters > and jump to the first matching position
t<字母>	Search backwards < letters > and jump to a letter before the first matching position (not used)
T<字母>	Search forward < letter > and jump to a letter after the first matching position (not used)

G Jump to the end of the document, 9G jump to the Nineth line, 9DD to delete 9 lines; GG delete a row; G jumps to the end of the document;

• In normal mode, jump to a line, use w jump to the beginning of a word, and then use dw the word delete
• In normal mode, use e jump to the end of a word and use ~ the letter that contains the cursor to capitalize or lower case

Copy paste and cut

A. Copying and pasting text

• Use replication in normal mode y

  • In normal mode, yy the entire line where the cursor is copied ( 3yy representing the replication of 3 rows)
  • In normal mode, y^ copy to the beginning of the line, or y0 . Does not contain the character at which the cursor is located.
  • In normal mode, y$ copy to end of line. The character where the light is contained.
  • In normal mode, yw copy a word.
  • In normal mode, y2w copy two words.
  • In normal mode, yG copy to the end of the text.
  • In normal mode, y1G copy to the beginning of the text.

• Use paste in normal mode p

  • In normal mode, p (lowercase) represents pasting to the cursor (bottom)
  • In normal mode, P (uppercase) means pasting to the front of the cursor (top)

B. Cut and paste

ddThe delete command is cut, and you dd can use it to paste each time you delete the contents of the document, p which allows us to implement a very refreshing function-the exchange of the upper and lower lines:

ddp, so simple, that it implements the fast Exchange cursor where the line is with the line below it

(3) Find and replace

substitution and revocation of characters (undo action)

A. Replace and revoke (undo) command

Both the Replace and undo commands are for normal mode operations

C td> (uppercase)

command	description
r +< Replace letter ;	replaces the letter that contains the cursor with the specified letter
R	Replace continuously until you press ESC
cc	replace Entire row, which deletes the row of the cursor and enters insert mode
cw	replace one word, delete one word, and enter insert mode
replace cursor later to end of line
~	Invert cursor case
u {n}	undo once or N operations
U (uppercase)	undo all modifications to the current line
ctrl+r	Redo, which is the action of undoing undo

• Input 11G , jump to 11 lines
• Enter FA to jump to the first a character
• Input r , and the input b,a character is replaced by the B character (practical)
• Enter a R replacement character, enter a new string, press ESC to return to normal mode (useful)
• Enter cc replace whole line character, enter new string, press ESC to return to normal mode after entering
• Enter cw replace one English word (word), press ESC to return to normal mode (useful)
• Input ~ , the case of the character in which the rollover cursor is located
• The input is C replaced with the end of the line, that is, the word will be replaced after the cursor is in place, press ESC to return to normal mode
• Enter u undo Last action

Fast Indent

A. Using commands to quickly adjust indent operations

• Normal mode input 15G , jump to 15 lines
• Input entire line in normal mode >> indent right (used to format code super cool)
• Enter the entire line in normal mode to the << left fallback
• Enter : command-line mode to set values in normal mode to shiftwidth control the number of characters in indentation and fallback shiftwidth command

b.shiftwidthCommand

Refers to >> the indentation (which can be abbreviated) from the previous command. sw enter : command line mode to shiftwidth set values to control the number of characters in indent and fallback to get the current set value

:set shiftwidth?

Set indent to 10 characters

:set shiftwidth=10

Enter ESC back into normal mode and try again to >> see if the indent changes

C. Adjusting the text position

Command line mode enter :ce (center) command to center the contents of the bank

Command line mode enter :ri (right) command to make our text

Command line Mode enter: le (left) command to leave the contents of the bank

Find A. Quick Find

Enter Normal mode / and then type the string you want to find and press ENTER to find it. ？is the same as the / function, but ？ looks up and / down. After entering the lookup, the input n and N can continue to find n the expression to continue the lookup, N reverse Lookup

B. Quick Find Exercises

Use VIM to open a file for editing

$ vim protocols

• Normal mode input /icmp find string ICMP
• Normal mode Enter to n find the next ICMP
• Normal mode input ？tcp up lookup string TCP
• Normal mode input N to find the last occurrence of TCP

C. Advanced Search

• Enter \* a word in normal mode to find where the cursor is located
• Normal mode input \# Ibid, but \* forward (up) to find, #则是向后 (bottom) find
• Normal mode g\* \* , but partially matches the word
• Normal mode g\# \# , but partially matches the word

Search for n The above, N continue to find command can still be used

(4) Getting Started with advanced features

Multi-file editingA. Editing multiple files with vim

There are two forms of editing multiple files, one being a parameter that is used before entering Vim is multiple files. Another is to enter vim and then edit the other files. Create two new files and edit them simultaneously

$ vim 1.txt 2.txt

Default Access 1.txt to file editing interface

• Command line mode input :n edit 2.txt file, you can ! :n! Force switch, the input of a file is not saved, just switch to another file
• Command line mode input :N edit 1.txt file, can be ! forced to :N! switch, the input in the previous file is not saved, just switch to another file

B. Open a new file after entering Vim

• Command line mode enter :e 3.txt open new file 3.txt
• Command line mode input :e# back to the previous file
• command-line mode input :ls to list previously edited documents
• Command line mode input :b 2.txt (or number) can be directly into the file 2.txt edit
• Enter :bd 2.txt (or number) in command-line mode to delete a file item from a previously edited list
• Command line mode input :e! 4.txt , new open file 4.txt, discard the file being edited
• Enter :f The file name you are editing in command line mode
• Input in command line mode :f new.txt , change the file being edited name to New.txt

C. Recovering files

If the document is not saved due to a power outage, you can use the recovery method, enter the vim -r document, input :ewcover 1.txt to restore

$ vim -r 1.txt

Visual ModeA. Introduction to Visual mode commands

• Enter in normal mode v (lowercase), enter the character selection mode, you can move the cursor, where the cursor will be selected. The selection is deselected when the V-meeting is pressed again.
• In normal mode input Shift+v (lowercase), enter the line selection mode, press V will be the entire row selection, you can move up and down the cursor select more rows, again, press once Shift+v can be deselected.
• In normal mode Ctrl+v (lowercase), this is the area selection mode, you can select the rectangular region, and then cancel the selection by one time Ctrl+v .
• Enter d Delete selection area in normal mode
• Enter y Copy selection area contents in normal mode

B. Visual mode command practice

• In normal mode 9G , jump to line 9th, enter Shift+v (lowercase v), enter the visual mode for row selection, select 5 rows, press >> indent, indent 5 rows into oneshiftwidth
• Enter in normal mode Ctrl+v (lowercase v), enter visual mode for rectangular area selection, select the first column character and then x delete the whole column

Windows OperationsA. Introduction to Windows Operations

Vim can open multiple windows in one interface for editing, which are called Vim windows. There are many ways to open the method, for example, you can use the input command line mode to :new open a new Vim window, and enter the window to edit a new file

Normal mode Ctrl+w can also be entered, but it Ctrl+w will conflict with Chrome's shortcut key to close the tab page.

• Command-line mode enter :sp 1.txt open new Landscape window to edit 1.txt
• Command-line mode :vsp 2.txt to open a new vertical window to edit 1.txt
• Ctrl-w ssplit the current window into two horizontal windows in normal mode
• Ctrl-w vsplit the current window into two vertical windows in normal mode
• In normal mode Ctrl-w q , it is: Q ends the split window. If you have input in a new window, you need to use the mandatory character! namely: q!
• Ctrl-w oOpen a window in normal mode and hide all previous windows
• Ctrl-w jmove to the following window in normal mode
• Ctrl-w kmove to the upper window in normal mode
• Ctrl-w hmove to the left window in normal mode
• Ctrl-w lmove to the right window in normal mode
• Ctrl-w Jmove the current window below in normal mode
• Ctrl-w Kmove the current window to the top in normal mode
• Ctrl-w Hmove the current window to the left in normal mode
• Ctrl-w Lmove the current window to the right in normal mode
• Ctrl-w -reduce the height of the window in normal mode
• Ctrl-w +increase the height of the window in normal mode

B. Windows operation exercises

Open the practice file$ vim 1.txt

• command-line mode input :new open a new vim window
• Command-line mode enter :sp 2.txt open new Landscape window to edit 2.txt
• Command-line mode enter :vsp 3.txt open new Landscape window to edit 3.txt
• If you use a non-Chrome browser, you can use Ctrl+w the jump between windows
• Enter :q! exit multi-window editing in command-line mode of different windows

Document EncryptionA. Creating an encrypted document

$ vim -x file1

Enter your password to confirm the password so that the next time you open, VIM will ask you to enter the password

executing external commands in vim

Enter command-line mode ! to execute external shell commands

• :!lsUsed to display the contents of the current directory
• :!rm FILENAMEUsed to delete a file named filename
• :w FILENAMESave the file you are editing in the current VIM as a filename file

Help Systemview Help in A.vim

• Press F1 vim to open your own preset help document in normal mode
• Enter :h shiftwidth shiftwidth The open Help file in command line mode
• Input :ver display version and parameters in command line mode

function SettingA.vim function Setting

Can be set when editing the file function settings, such as the command line mode input :set nu (display number of lines), set value exit Vim will not be saved. To permanently save the configuration, you need to modify the Vim configuration file. Vim configuration file ~/.vimrc , you can open the file for modification, but be careful not to affect the normal use of vim

B. Get the current settings

• Enter :set or :se display all modified configurations in command line mode
• command-line mode input :set all displays all the SetPoint values
• Command-line mode :set option? to enter a setting value that displays option
• Command line mode to enter the :set nooption cancel current set value

description of the C.set function

• :set autoindent(ai)automatic indentation of input settings in command line mode
• Command line mode input :set autowrite(aw) set AutoArchive, default not open
• Enter or in command line :set background=dark mode light , set the background style
• Command line mode input :set backup(bk) set automatic backup, default not open
• Command line mode input : set cindent(cin) set C language style indent

3.Linux System Programming

(1) Use of GCCcompiler use of GCC

 

Second, the problems encountered and sentiment:

Early groping vim time with too much, followed the tutorial done two times, think some instructions still do not remember, sad~

In the test and run the teacher layout code, I first put a few code to change the file name and save, but there is no way to call a few code to each other, and the book is very obscure, difficult to read.

When I was doing the experiment building GDB use, is not able to read the experimental instruction book content, such as: "GDB start, you can add some gdb start switch, the detailed switch can be used gdb-help view"

Do not know how to add the start switch and so on, I hope that teachers can be more involved in class, after all, the compiler is also a necessary tool for programming ^_^

Information Security system design basics second week study summary